1. Field
Embodiments of the inventive concept relate to a liquid crystal display capable of reducing image sticking due to high kickback voltage generated in a high-resolution liquid crystal display.
2. Description of Related Technology
A liquid crystal display (LCD) is a type of flat panel displays (FPDs), which is the most widely used these days, and is configured such that a liquid crystal layer is interposed between two substrates having electrodes, so that liquid crystal molecules of the liquid crystal layer are rearranged upon applying voltage to the electrodes, thereby adjusting the amount of light transmitting through the liquid crystal layer.
A liquid crystal display (LCD) is slim but has a low side visibility compared to a front visibility. In order to overcome the disadvantage, many methods for arrangement of molecules in a liquid crystal and driving methods have been developed. In order to achieve wide viewing angle performance, studies on a plane to line switching (PLS) LCD in which a pixel electrode and a common electrode are formed on one substrate have been continuously carried out.
Especially, with increasing demands for high-resolution images, LCDs including pixels equal to or more than 500 PPI (pixels per inch) (that is, the LCDs in which approximately 500 or more pixels are included in an area of 1 inch wide by 1 inch high) have been continuously studied.
In the case of a high resolution LCD, as the number of pixels increases, the size of the pixel decreases and the area of a pixel electrode or a common electrode, which is included in the pixel, also decreases such that storage capacitance (Cst) is lowered.
Kickback voltage (Vkb) is particularly affected by the storage capacitance (Cst) and it is calculated using the following equation.
                              V          kb                =                                            C              gs                                                      C                st                            +                              C                gs                            +                              C                                  lc                  ⁢                                                                                                                      ⁢                      V            p                                              [                  Equation          ⁢                                          ⁢          1                ]            wherein Cgs denotes parasitic capacitance between a gate electrode and a source electrode, Clc denotes a capacitance of a liquid crystal layer, and Vp denotes a voltage applied to a pixel electrode.
When the storage capacitance (Cst) decreases, the kickback voltage (Vkb) increases and the high kickback voltage (Vkb) affects a pixel electrode or a common electrode in a pixel, thereby increasing voltage ripple, such that image sticking occurs on a screen and, thus, resolution is lowered.
In order to solve such problems, an insulating layer included in an LCD is formed to be thick, but the thick insulating layer causes the LCD to be also thicker.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding effective filing dates of subject matter disclosed herein.